Modeling and Forecasting Nigerian Crude Oil Exportation: Seasonal Autoregressive Integrated Moving Average Approach

In the last few decades, crude oil (petroleum) has claimed the topmost position in Nigerian export list, constituting a very fundamental change in the structure of Nigerian international trade. This paper is intended to model and forecast Nigerian monthly crude oil exportation (in barrels) by applying seasonal autoregressive moving average (SARIMA) into the same data collected between January, 2002 to December, 2011. Result reveals an upward trend of the series which became stationary at 1st difference, a sharp drop between 2007 and 2009 and autocorrelation function with significant spikes at lag 1, 7 and 12 suggesting the presence of seasonality in the series. Based on Akaike Information Criterion (AIC), Schwartz Bayesian Information Criterion (SBIC) and Hannan-Quinn Information Criterion (HQC), the best model was SARIMA (1, 1, 1) x (0, 1, 1) 12. The diagnosis on such model was confirmed, the error was white noise, presence of no serial correlation and a forecast for current and future values within 24 months period was made which indicates that the crude oil exportation is fairly unstable.